A magnetometer is an instrument used to measure the strength and/or direction of the magnetic field in the vicinity of the instrument. Many electronic devices exist that utilize a magnetometer for taking measurements for a particular application, e.g. metal detectors, geophysical instruments, aerospace equipment, and mobile communications devices such as cellular telephones, PDAs, smart phones, tablet computers, etc., to name a few.
Devices that comprise a magnetometer and have a display and processing capabilities, e.g., a smart phone, may include a compass application for showing a direction on the display.
Mobile communication devices, such as those listed above, can operate in many different locations and under various circumstances. Changes in the environment in which the device operates can affect the operation of the magnetometer. As such, the magnetometer may need to be calibrated at certain times.